Development of systemic lupus erythematosus in a patient with selective complete C1q deficiency

A 7-year-old male with recurrent erythematous and desquamated skin lesions and respiratory infections was diagnosed as selective complete C1q deficiency following detailed studies of the complement system. His asymptomatic sister also had selective complete C1q deficiency. During a follow up period of 3 years, his skin lesions persisted, he suffered from recurrent bronchopneumonias and glomerulonephritis developed. Renal function deteriorated with the appearance of anti-DNA antibodies. Renal biopsy was consistent with systemic lupus erythematosus. The patient was treated with immunosuppressive drugs, but died of renal failure. It is postulated that in this patient defective clearance of ant…